Objective To study the expression of NLRP3 inflammasome and its downstream inflammatory factors in patients with chronic obstructive pulmonary disease (COPD) and healthy controls, and to reveal the effect and significance of NLRP3 inflammasome in the pathogenesis of COPD. Methods Forty patients with acute exacerbation COPD (AECOPD) who were hospitalized from November 2016 to May 2017 were recruited in the AECOPD group, and recruited in the stable COPD group when they entered the stable stage. Forty healthy individuals were recruited in the control group. General information and peripheral blood were collected from each subject. The levels of NLRP3 mRNA and caspase-1 mRNA in peripheral blood mononuclear cells were measured by real-time PCR. The levels of IL-18 and IL-1β were measured by enzyme-linked immunosorbent assay. Results The levels of NLRP3 mRNA, IL-18 and IL-1β in the AECOPD patients were significantly higher than those in the stable COPD group [2.11±0.77, 12.79 (7.10, 43.13) pg/ml, 17.02 (8.36, 52.21) pg/ml vs. 1.60±0.44, 10.66 (6.32, 18.59) pg/ml, 13.34 (7.07, 16.89) pg/ml, all P<0.05] . The levels of NLRP3 mRNA, IL-18 and IL-1β in the AECOPD patients were significantly higher than those in the control group [2.11±0.77, 12.79 (7.10, 43.13) pg/ml, 17.02 (8.36, 52.21) pg/mlvs. 1.00±0.49, 6.29 (4.73, 7.93) pg/ml, 5.93 (4.81, 9.67) pg/ml, all P<0.05]. The levels of NLRP3 mRNA, IL-18 and IL-1β were significantly higher in the stable COPD group than the control group [1.60±0.44, 10.66 (6.32, 18.59) pg/ml, 13.34 (7.07, 16.89) pg/mlvs. (1.00±0.49, 6.29 (4.73, 7.93) pg/ml, 5.93 (4.81, 9.67) pg/ml, all P<0.05]. Correlation analysis showed that the plasma IL-18 level was positive correlated with leukocyte count and neutrophil percentage in the AECOPD group (r=0.372, P<0.05;r=0.386, P<0.05). The expression of NLRP3 mRNA in the AECOPD group and stable COPD group were positively correlated with the CAT score (r=0.387, P<0.05;r=0.399, P<0.05) . Conclusion NLRP3 inflammasome is involved in the inflammatory response in COPD patients.